Cell-type filter cartridges have long been known and are increasingly used in a variety of situations. These type of filter cartridges are typically fabricated from individual cells generally having two layers of filter media separated from each other. Liquid typically flows from the outside of the filter medium into the space between the layers of the filter media toward the central portion of the cell. A significant advantage to cell-type filter cartridges is that the surface area of filter material is quite large when compared to the total volume of an assembled cell-type filter cartridge.
Disposed between each filter medium is a separator which is typically formed in the shape of disks having ribs radially extending from the central aperture in a spoke-like pattern. In addition to separating the two layers of filter media, it provides for fluid flow from the filter media toward the central aperture of the filter media.
The separator disk has stiffening members formed at the central aperture of the cell which are attached to a plurality of separating ribs to provide a rigid, box-like structure sufficient to impart substantial cantilever strength to the ribs. Further, one of the stiffening disks is positioned proximate the ends of the separator ribs in order to act as a loadbearing surface to prevent media intrusion of the filtering medium and to prevent blocking the area of the flow path with the filtered liquid. Accordingly, one distinct advantage in this type of separator is that during backwashing or reverse flow (i.e., fluid flow from the central aperture of the filter cell out toward the surface of the filter medium) damage to the filter media is minimized or ameliorated.
Filter cartridges use a variety of filter media for filtering many fluids. Examples of such media and uses may be found, for example, in U.S. Pat. No. 4,617,128 "Particulate Filter Aid, Filter Bed Process" dated Oct. 14, 1986, to Ostreicher; U.S. Pat. No. 4,309,247 "Filter and Method of Making Same" dated Jan. 5, 1982 to Hou et al.; U.S. Pat. No. 4,305,782 "Filter and Method of Making Same" dated Dec. 15, 1981 to Ostreicher et al.; U.S. Pat. No. 4,007,113 "Particulate Filter Medium and Process" dated Feb. 8, 1977 to Ostreicher; and U.S. Pat. No. 4,007,114 "Fibrous Filter Medium and Process" dated Feb. 8, 1977 to Ostreicher. All of the foregoing patents are incorporated herein by reference.
Use of a cell-type filter cartridge may be also found in U.S. Pat. No. 4,361,486 "Filter Media, Method for Oxidizing and Removing Soluble Iron, Method for Removing Inactivating Microorganisms and Particulate Filter Aid" issued Nov. 30, 1982 to Hou et al. which is incorporated herein by reference.
A process for manufacturing filter cells is described in U.S. Pat. No. 4,347,208 "Method of Making filter Cell Having Sealed Periphery" issued Aug. 31, 1982 to Southall. In this patent, a filter cell cartridge is described which comprises a plurality of filter cells. Each of the filter cells is comprised of filter media having a conical separator therebetween with the periphery or edges of the filter cell being held together and sealed by an injection-molded flange.
A method for disposing a netting or mesh on the outside of the filter material is disclosed in U.S. Patent No. 4,881,313 "Method of Forming a Cell Filter With an Exposed Surface" issued to Artinyan et al. In this patent, the surface area of filter exposed to unfiltered fluid has disposed thereon a netting thereby preventing flaking, cracking and the like of filter media during backflow or cleaning operations. The netting is secured to the cell by a molded circumferential retainer and a circumferential centrally disposed ring.
Generally, all of the aforementioned filter cartridges perform as anticipated during normal operating conditions. As can be expected after extended use, the filtering capacity of the filter media diminishes accordingly. The filter cartridges are replaced by grasping the periphery or edge of the uppermost filter cell, and then carefully lifting the attached filters away from the filter housing. This method relies on the strength of the individual wet cells as well as that of the bands which interconnect the multiple filter cells, to prevent any one of the attached filter cells from breaking apart. Alternatively, if the construction of the filter housing permits, the bottom filter may be grasped around its periphery and then removed by carefully lifting the cartridge up and out of the filter housing. Both of the aforementioned methods are problematic because of the increased weight of a wet filter cartridge as compared to the weight of a dry filter cartridge. This increased load is generally concentrated toward the center of the cartridge, thus resulting in the likelihood of the cartridge separating during the lifting operation.
A wet filter cartridge that breaks during removal from a filter housing causes several problems. Primarily, if the cartridge breaks while still in the vicinity of the housing, the particulate matter removed by the filters may re-enter the housing, thus requiring additional cleaning operations in and around the housing.
Although it is common to provide a handle for lifting and carrying bulky items, the prior art does not disclose a handle that provides a method of attaching the handle to a wet, bulky, used filter cartridge. Nor does the prior art provide a filter cartridge with a handle integrally disposed thereon. The present invention provides such a handle, thereby increasing the convenience to and productivity of the technician utilizing the invention.